#57 drill size

    A #57 number (wire-gauge) drill is 0.0430 in (1.092 mm).

    Decimal inch
    0.0430
    Millimeters
    1.092
    Nearest 1/64
    3/64" (-0.0039)
    Type
    number (wire-gauge) drill

    Nearest equivalents in other systems

    Drills closest to #57
    SystemDrillInchmmDifference
    Fractional3/64"0.04691.191+0.0039 in
    Metric1.1 mm0.04331.100+0.0003 in

    Speeds and feeds: in mild steel an HSS drill starts at about 7,990 RPM and 0.0010 in/rev (7.99 IPM); in 6061 aluminum about 22,210 RPM.

    #57 drill speeds and feeds by material

    Jobber-length twist drill, D = 0.0430 in. RPM = 3.82 × SFM ÷ D, rounded to 10. Feed per rev scales with diameter and material; IPM = RPM × IPR.

    #57 drilling speeds
    MaterialHSS SFMHSS RPMCarbide SFMCarbide RPMFeed (in/rev)HSS IPMCarbide IPM
    Aluminum (6061)25022,21060053,3000.001022.253.3
    Brass / free-machining15013,32040035,5300.000810.728.4
    Low-carbon steel (1018)907,99030026,6500.00107.9926.6
    Alloy steel (4140, annealed)706,22025022,2100.00106.2222.2
    Stainless 304403,55015013,3200.00072.499.32
    Gray cast iron807,11025022,2100.00064.2713.3
    Titanium 6Al-4V252,2201008,8800.00051.114.44
    Plastics (acetal)30026,65050044,4200.001745.375.5

    Small drills: the computed RPM is above most spindles. Run at your spindle's maximum and keep the feed per rev; feed drops in proportion.

    Metric: Vc (m/min) = SFM × 0.3048; feed (mm/rev) = in/rev × 25.4. In steel, 7,990 RPM × 0.025 mm/rev = 203 mm/min.

    Worked example: #57 drill in 1018 steel

    1. HSS drill in low-carbon steel: 90 SFM.
    2. RPM = 3.82 × 90 ÷ 0.0430 ≈ 7,990 RPM.
    3. Feed for a 0.043 in drill in mild steel ≈ 0.0010 in/rev.
    4. IPM = 7,990 × 0.0010 = 7.99 IPM.

    Peck cycle by hole depth

    #57 drill: depth and canned cycle
    DepthCyclePeckNote
    3×D = 0.129 in (3.3 mm)G81 (no peck)NoneUp to 3×D a sharp drill clears chips on its own.
    5×D = 0.215 in (5.5 mm)G73 chip-break1 × DChip-break pecks; full retract if chips pack (soft aluminum, stainless).
    8×D = 0.344 in (8.7 mm)G83 full retract0.5-1 × D, shrinking with depthRetract to clear chips; reduce feed ~10-20% past 5×D.

    Taps that use a #57 drill

    No standard UNC, UNF or metric tap in our tables calls for a #57 drill. Use it for clearance, pilot or reamer prep holes.

    Nearest drills

    • 1.1 mm: 0.0433 in / 1.100 mm (+0.0003 in)
    • #58: 0.0420 in / 1.067 mm (-0.0010 in)
    • 1.05 mm: 0.0413 in / 1.050 mm (-0.0017 in)
    • #59: 0.0410 in / 1.041 mm (-0.0020 in)

    Common questions

    What is a #57 drill in decimal and mm?
    0.0430 in, or 1.092 mm; nearest fractional drill: 3/64" (0.0469 in, +0.0039 in); nearest metric drill: 1.1 mm (0.0433 in, +0.0003 in).
    What RPM for a #57 drill in steel?
    In low-carbon steel (1018) an HSS #57 drill (0.0430 in) runs about 7,990 RPM at 90 SFM; a carbide drill about 26,650 RPM at 300 SFM. RPM = 3.82 × SFM ÷ D.
    What feed for a #57 drill?
    About 0.0010 in/rev in mild steel, 0.0010 in/rev in aluminum and 0.0007 in/rev in 304 stainless. At 7,990 RPM that is 7.99 IPM in steel (IPM = RPM × IPR).
    What RPM for a #57 drill in aluminum?
    22,210 RPM with HSS (250 SFM) or up to 53,300 RPM with carbide (600 SFM), feeding about 0.0010 in/rev.
    What size is a #57 drill?
    0.0430 in / 1.092 mm. The nearest other drills are 1.1 mm (0.0433 in), #58 (0.0420 in), 1.05 mm (0.0413 in).

    Nearby drill sizes

    Sources

    Material feed multipliers (aluminum 1.3×, brass 1.1×, 4140 0.85×, stainless and titanium 0.7× the mild-steel feed) are JobLine estimates. Peck guidance is JobLine shop practice. Use your drill maker's data first.

    Free for machinists & programmers

    Put your skills on a free talent profile

    Machines, controls, certs and saved calculations in one profile shops can find.

    Create free profile
    For your shop

    Bring shift handoffs to your shop

    Stop losing job status between shifts. Every station's notes, counts and issues, handed off cleanly.

    See shift handoffs